Rising sea levels could threaten 180 U.S. coastal cities by 2100, according to new research led by University of Arizona scientists.
The Gulf and southern Atlantic coasts will be particularly hard hit. Miami, New Orleans, Tampa, Fla., and Virginia Beach, Va. could lose more than 10% of their land area by 2100 (the average estimated land loss across the 180 cities is 9%).
The research is the first analysis of vulnerability to sea-level rise that includes every U.S. coastal city in the lower 48 with a population of 50,000 or more.
The latest scientific projections indicate that by 2100, the sea level will rise about 1 meter–or even more. One meter is about 3 feet.
At the current rate of global warming, sea level is projected to continue rising after 2100 by as much as 1 meter per century.
"According to the most recent sea-level-rise science, that’s where we’re heading," said lead researcher Jeremy L. Weiss, a senior research specialist in the University of Arizona’s department of geosciences. "Impacts from sea-level rise could be erosion, temporary flooding and permanent inundation."
The coastal municipalities identified in the reserach had 40.5 million people living in them, according to the 2000 U.S. Census. Twenty of those cities have more than 300,000 inhabitants.
Weiss and his colleagues examined how much land area from the 180 municipalities could be affected by 1 to 6 meters of sea-level rise.
"With the current rate of greenhouse gas emissions, the projections are that the global average temperature will be 8 degrees Fahrenheit warmer than present by 2100," said Weiss.
"That amount of warming will likely lock us into at least 4 to 6 meters of sea-level rise in subsequent centuries, because parts of the Greenland and Antarctic ice sheets will slowly melt away like a block of ice on the sidewalk in the summertime."
At 3 meters (almost 10 feet), on average more than 20% of land in those cities could be affected. Nine large cities, including Boston and New York, would have more than 10% of their current land area threatened. By 6 meters (about 20 feet), about one-third of the land area in U.S. coastal cities could be affected.
"Our work should help people plan with more certainty and to make decisions about what level of sea-level rise, and by implication, what level of global warming, is acceptable to their communities and neighbors," said co-author Jonathan T. Overpeck, a UA professor of geosciences and of atmospheric sciences and co-director of UA’s Institute of the Environment.
Weiss, Overpeck and Ben Strauss of Climate Central in Princeton, N.J., will publish their paper, "Implications of Recent Sea Level Rise Science for Low-Elevation Areas in Coastal Cities of the Conterminous U.S.A.," in Climatic Change Letters. The paper is scheduled to go online this week.